Steel characteristics
Brass is an alloy of copper and zinc
White copper is an alloy of copper and nickel
Bronze is an alloy of copper and elements other than zinc and nickel, mainly tin bronze, aluminum bronze, etc.
Red copper is copper with a high copper content, and the total content of other impurities is less than 1%.
Red copper is pure copper, also known as red copper. The density of pure copper is 8.96 and the melting point is 1083℃. It has good electrical and thermal conductivity, excellent plasticity, and is easy to process by hot pressing and cold pressing. It is widely used in the manufacture of wires, cables, brushes, special electro-etching copper for electric sparks, and other products that require good conductivity.
It is named because of its purple-red color. It is not necessarily pure copper. Sometimes a small amount of deoxidizing elements or other elements are added to improve the material and performance, so it is also classified as a copper alloy. According to the composition, Chinese copper processing materials can be divided into four categories: ordinary copper (T1, T2, T3, T4), oxygen-free copper (TU1, TU2 and high-purity, vacuum oxygen-free copper), deoxidized copper (TUP, TUMn), and special copper with a small amount of alloy elements (arsenic copper, tellurium copper, silver copper).
The electrical conductivity and thermal conductivity of copper are second only to silver, and it is widely used to make conductive and thermal conductive equipment. Copper has good corrosion resistance in the atmosphere, seawater, certain non-oxidizing acids (hydrochloric acid, dilute sulfuric acid), alkalis, salt solutions and various organic acids (acetic acid, citric acid), and is used in the chemical industry. In addition, copper has good weldability and can be processed into various semi-finished and finished products through cold and hot plastic processing. In the 1970s, the output of copper exceeded the total output of other types of copper alloys.
Trace impurities in copper have a serious impact on the electrical and thermal conductivity of copper. Among them, titanium, phosphorus, iron, silicon, etc. significantly reduce the electrical conductivity, while cadmium, zinc, etc. have little effect. Oxygen, sulfur, selenium, tellurium, etc. have very low solid solubility in copper and can form brittle compounds with copper. They have little effect on conductivity, but can reduce processing plasticity. When ordinary copper is heated in a reducing atmosphere containing hydrogen or carbon monoxide, hydrogen or carbon monoxide easily reacts with cuprous oxide (Cu2O) at the grain boundary to produce high-pressure water vapor or carbon dioxide gas, which can cause copper to crack. This phenomenon is often called the "hydrogen disease" of copper. Oxygen is harmful to the weldability of copper. Bismuth or lead forms a low-melting point eutectic with copper, making copper hot and brittle; and when brittle bismuth is distributed in the form of a thin film at the grain boundary, it makes copper cold and brittle. Phosphorus can significantly reduce the conductivity of copper, but it can increase the fluidity of copper liquid and improve weldability. Appropriate amounts of lead, tellurium, sulfur, etc. can improve machinability.
Brass: Copper alloys with zinc as the main additive element have a beautiful yellow color and are collectively called brass. Copper-zinc binary alloys are called ordinary brass or simple brass. Brasses with more than three elements are called special brass or complex brass. Brass alloys with a zinc content of less than 36% are composed of solid solutions and have good cold working properties. For example, brass with a zinc content of 30% is often used to make cartridge cases, commonly known as cartridge brass or 73 brass. Brass alloys with a zinc content between 36% and 42% are composed of solid solutions, of which 64 brass with a zinc content of 40% is the most commonly used. In order to improve the performance of ordinary brass, other elements such as aluminum, nickel, manganese, tin, silicon, lead, etc. are often added. Aluminum can improve the strength, hardness and corrosion resistance of brass, but reduce its plasticity, making it suitable for sea-going condensers and other corrosion-resistant parts. Tin can improve the strength and corrosion resistance of brass to seawater, so it is called naval brass, which is used for ship thermal equipment and propellers. Lead can improve the cutting performance of brass; this easy-to-cut brass is often used as watch parts. Brass castings are often used to make valves and pipe fittings, etc.
Bronze: Originally refers to copper-tin alloy, and later copper alloys other than brass and nickel silver are called bronze, and the name of the first main added element is often added before the name of bronze. Tin bronze has good casting performance, anti-friction performance and mechanical properties, and is suitable for manufacturing bearings, worm gears, gears, etc. Lead bronze is a bearing material widely used in modern engines and grinders. Aluminum bronze has high strength, good wear resistance and corrosion resistance, and is used to cast high-load gears, bushings, marine propellers, etc. Beryllium bronze and phosphor bronze have high elastic limits and good conductivity, and are suitable for manufacturing precision springs and electrical contact elements. Beryllium bronze is also used to manufacture spark-free tools used in coal mines, oil depots, etc.
Nickel silver: Copper alloy with nickel as the main added element. Copper-nickel binary alloy is called ordinary nickel silver; nickel silver alloy with manganese, iron, zinc, aluminum and other elements is called complex nickel silver. Industrial nickel silver is divided into two categories: structural nickel silver and electrical nickel silver. Structural nickel silver is characterized by good mechanical properties and corrosion resistance, and beautiful color. This type of white copper is widely used in the manufacture of precision machinery, chemical machinery and ship components. Electrical white copper generally has good thermoelectric properties.
Manganese copper, constantan and copper are manganese white coppers with different manganese contents. They are materials used to manufacture precision electrical instruments, varistors, precision resistors, strain gauges, thermocouples, etc.
